The FDA has approved fostemsavir as a new treatment for HIV-1 patients who are failing their current treatments, according to a release from the manufacturer. 

The 600 mg extended-release tablets are approved in combination with other antiretroviral therapies for heavily treatment-experienced adults. The approval came after the phase 3 BRIGHTE study. The trial included 371 patients, of which 272 were randomized to receive either fostemsavir or placebo and their “failing regimen” for eight days. After those eight days, the patients received fostemsavir twice daily and an investigator-selected optimized background therapy. The nonrandomized cohort had “no fully active and approved antiretroviral agents” at screening, according to the release. They were treated with fostemsavir at the onset of the trial, along with the optimized background therapy. 

Results of the trial showed fostemsavir was superior to placebo in adjusted mean decline in HIV-1 RNA from Day 1 at day eight in the randomized cohort (0.79 vs. 0.17 log10 copies/mL decline, respectively; P<0.0001, Intent to Treat Exposed population). HIV-1 RNA<40 copies/mL was achieved in 53% and 60% at weeks 24 and 96 respectively. 

“As a novel HIV attachment inhibitor, fostemsavir targets the first step of the viral lifecycle offering a new mechanism of action to treat people living with HIV,” said Jacob P. Lalezari, MD, CEO, and director of Quest Clinical Research. “In the BRIGHTE study, fostemsavir in combination with other ARVs effectively achieved and maintained long-term viral suppression and demonstrated clinically meaningful rise in CD4+ T-cell count even among heavily immunocompromised patients.” 

The most common adverse reactions observed in ≥5% of both the randomized and nonrandomized groups were nausea, fatigue, and diarrhea. The most common adverse events leading to discontinuation were related to infections and were reported in 3% of patients. 

Fostemsavir was previously granted Fast Track and Breakthrough Therapy designations by the FDA. It is currently under review by the European Medicines Agency, with additional regulatory applications expected this year and next.